<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    const person = {
      name: "jack",
      age: 21,
      language: ['java', 'js', 'css']
    }
    console.log(Object.keys(person));
    console.log(Object.values(person));
    console.log(Object.entries(person));
    
    //assign
    let target = { name: 'zhangsan' };
    let source1 = { age: 24 };
    let source2 = { gender: '男' };
    Object.assign(target, source1, source2);
    console.log(target);
  </script>
</body>

</html>